The Protein Chemistry Section is dedicated to collaborative projects involving the structural analysis of proteins. The projects are derived from all of the other sections in the program and are categorized as addressing problems in DNA synthesis, transcriptional control, and RNA processing as they relate to the oncogenic transformation of cells by tumor viruses. These projects fall into three categories (i) proteins involved in DNA replication and chromatin assembly (Section I and II); (ii) proteins involved in transcriptional control of viral and cellular genes (Sections III and VI); and (iii) proteins involved in RNA processing and translation (sections IV and V). The methodologies involved in these investigations involve four areas: separations, protein sequencing, analysis of modifications, and peptide synthesis. The specific aims are: 1. To separate proteins and their peptide fragments by chromatographic and electrophoretic methods: 2. To perform sequence and amino acid analysis of proteins and their peptide fragments. 3. To chemically determine and map sites of post- translational modifications: 4. To synthesize peptides for use as antigens and in functional analyses of proteins.